Chromable monoazo dyes



Patented Aug. 17, 1948 UNITED STATES PATENT OFFICE CHROMABLE MONOAZO DYEIS Achille Conzetti, Basel, Switzerland, assignor to J. R. Geigy A.-G., Basel, Switzerland No Drawing. Application April 5, 1946, Serial No.

659,887. In Switzerland April 17, 1945 3 Claims. (01. 260-497) 1 It has been found that, when coupling diazotised 4-chlor-5-nitro-2-aminophenol-G-sulfonic acid, which may further be substituted in 3-posi- 'tion by chlorine, with :8-dichlor-1-naphthol,

Example 1 50.4 parts of 4-chlor-5-nitro-2-aminophenolfi-sulfonic acid are diazotised in an indirect way according to conventional methods. The diazo body is treated with small quantities of bicarbonate, until it reacts violet to Congo and then allowed to run into an ice-cold solution of 45.8 parts of 5:8-dichlor-1-naphthol in 680 parts of water made slightly mimosa-alkaline by addition of 30 parts by volume of 29% caustic soda lye. Then further 30 parts of calcined sodium carbonate and ice are added. After complete coupling the whole is heated to 90 C'., salted out with 100 parts of sodium chloride and hot filtered.

The dyestufl' dyes wool from an acid bath in red-violet shades being converted, when afterchromed, into light-fast blue-grey shades.

Example 2 60.6 parts of 3:4-dichlor-5-nitro-2-aminophenol-G-sulfonic acid are diazotised in water according to usual methods. The golden crystal- The diazo component is made by producing benzoxazolone from the 3:4-dichlor-2-amino phenol-G-sulfonic acid by means of phosgene, nitrating the resulting benzoxazolone and again opening the oxazolone ring with alkaline agents, whereupon the o-aminophenol derivative is obtained.

What I claim is:

1. A chromable azo dyestuff of the formula HOaS N=N OzN X wherein X represents a member selected from the group consisting of H and Cl.

2. A chromable azo dyestufi of the formula 3. A chromable azo dyestufl' of the'formula ACHILIE CONZETTI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS lised diazo body is treated with small quantities Number Name Date of bicarbonate until it reacts violet to Congo, 2,109,806 Straub et a1. Mar. 1, 1938 then the mixture is introduced into a solution 2,178,054 Straub et a1 Oct. 31, 939

which is obtained by dissolving 44.6 parts of 2,305,747 Straub et al Dec. 22, 1942 5:8-dichloronaphthol in 680 parts of water, which 2,353,675 Knecht et a1 July 18, 1944 was made mimosa-alkaline by addition of 28 parts by volume of 29% caustic soda lye. Then 33 parts FOREIGN PATENTS of sodium carbonate and ice are added thereto. Number Country Date After several hours the dyestufi' is filtered off. 498,575 Great Britain J 10, 1939 The dyestufl dyes wool from an acid bath in 513,337 Great Britain Oct. 10, 1939 blue-violet shades, which, on after-chroming or 517,558 France Dec- 1920 according to the one-bath chroming method, are 541,692 Great Britain Dec. 8, 1941 converted into pure greenish shades. 

